• Large in scale, complex in nature and Economics Planning of Super more expensive in construction. Tall Buildings in Asia Pacific • No previous study on super tall Introduction Cities buildings. •Examine the economics planning of Dr Paul H K Ho super tall office buildings in Asia Pacific cities.

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• Tall buildings - in the range of 30 to 50 Building Cases City Height Floors Year stories 1. Taipei 101 Tower Taipei 509 m 101 2004 Research Method

• Super tall buildings - in excess of 50 Sample Cases 2. Petronas Tower 1 Kuala Lumpur 452 m 88 1998 stories 3 Petronas Tower 2 Kuala Lumpur 452 m 88 1998 • Case studies of the Asia Pacific’s 10 4 Jin Mao Tower Shanghai 421m 88 1998 tallest buildings. 5. International Finance Centre Hong Kong 415 m 88 2003 • Represent the world’s 15 tallest 6. CITIC Plaza Guangzhou 391 m 80 1997 buildings. 7. Shun Hing Square Shenzhen 384 m 69 1996 • The tallest buildings in its cities. 8. Central Plaza Hong Kong 374 m 78 1992 • Landmark buildings designed by 9. Bank of China Tower Hong Kong 367 m 70 1990 renowned consultants. 10. The Center Hong Kong 346 m 73 1998 Asia Pacific’s 10 Tallest Buildings

3 4 Lettable to Gross Floor Area to Gross Ratio Lettable • The lettable to gross floor area ratio Plan Shape of Building depends on the size of floor plate in

Size ofSize Floor Plate: relation to its service core. • It was found that – The site areas are large and floor plate design is not constrained by its maximum site coverage. – The floor plate is large, ranging from approximately 2,100m2 to 2,800m2. – All can achieve a high lettable to gross floor area ratio of about 80%.

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1 • External wall is a cost significant • Lease span is the clear distance from

Wall to Floor Area Ratio element. the building core to the external wall.

Size of Floor Plate: of Floor Size It was found that • It was found that

Lease Span – The common lease span is 12m, – The average wall to floor area ratio ranging from 9.80m to 13.89m. is 0.34. – Bank of China has the longest lease – Jin Mao Tower has the lowest wall span of 17m at its lower floors. to floor area ratio of 0.30. • It is desirable to have as few columns – Petronas Towers have the highest as possible within the lease span area. wall to floor area ratio of 0.40. It was found that – If Petronas Towers are excluded, – except Central Plaza, all buildings the average wall to floor area ratio have no columns. will become 0.33. – In Central Plaza there is only one column at the middle. 7 8

• The floor height consists of two • Structural floor system can have an

aspects; floor-to-floor height and Structural FloorSystems impact on the overall floor height. floor-to-ceiling height. • It was found that Floor Height • It was found that the floor-to-ceiling Floor Height: – Traditional concrete flooring system height ranges from 2.60m to 2.80m. in CITIC Plaza and Central Plaza. • Raised floor is provided in some – Steel flange beam with composite buildings and increases the floor-to- metal deck and concrete flooring floor height. system in remaining buildings. • It was found that the common floor- – No direct relation between to-floor height is 4.0m, ranging from structural floor systems and its overall 3.73m to 4.20m. floor height.

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• Large podium floors at lower levels to • Tapering has a significant accommodate commercial functions. improvement in the overall building structural behaviours to wind force.

Building Form • Setback in main tower to Building Form accommodate different functions. • It was found that many buildings – No much variance of window size have a slightly tapered building and proportion due to different shape at its top floors. floor-to-floor heights. – A single structural system and a single construction material.

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2 • The size of service core should be Service Core Construction • The core material can be built from

Service Core Design reduced to an acceptable minimum. steel or concrete. • It was found that • Structural steel and drywall construction is less common. – Central core approach in all • High-strength concrete to reduce the buildings, except Bank of China thickness of service core walls. Tower. • Service core construction on the – Central core as a structural element critical path programme. to provide stability. • By using slip-form or jump-form –Its internal layout is changed. techniques, a 3 to 4-day cycle is achievable for core wall construction. • This speed is similar to steel construction.

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• The structural system has a great • There are limited supply of quality

impact not only on exterior aesthetics Structural Materials structural steel and experienced Structural Systems of a building, but also on its interior contractors in steel fabrication. space planning. • Steel construction is more expensive • Two common structural systems for than reinforced concrete. super tall buildings • Very high-strength concrete (over – composite mega-columns with 100MPa) can be produced with no central core and outriggers system difficult from materials available from – reinforced concrete tube-in-tube local market. with or without outriggers system such

15 16 Vertical Transportation Systems Vertical Transportation • Sky-lobby system is adopted to keep • The structural system is the most the service core within a reasonable important criterion for super tall size. buildings. – This system was found in Central Plaza Conclusions • With sufficient site area, the building and Shun Hing Square. can be designed to have a larger floor plate, and a longer lease span. • Another solution is the double-deck lift system. • Square or similar plan is the most common geometry in super tall • It can be used with the sky-lobby buildings. system to further reduce lift shafts. • Central core approach is commonly –This double-deck, sky-lobby system was used in super tall buildings. found in Taipei 101 Tower, Petronas Towers and International Finance Centre.

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